This invention relates to universal joint assemblies in general, and more specifically to flange yokes. Universal joint assemblies, particuarly those used in vehicle drivelines, are designed for rapid rotation under substantial torsional loads. As is well known in the art, universal joint assembly components, such as yoke members, must be carefully balanced to perform adequately. Balancing is especially important for components such as flange yokes, which have a relatively high proportion of mass positioned a substantial distance from their axes of rotation.
Individual universal joint components such as flange yokes are balanced prior to their assembly. A typical balancing process for yokes includes drilling holes in the finished yoke to remove excessive mass from its "heavy" side. A typical practice in balancing flange yokes includes drilling several shallow balance holes on the back face of the flange near its outer periphery. The traditional practice has been to move the balance holes radially outwardly to the periphery of the flange and the farthest away from the center of rotation of the flange to be most effective.
Several problems exist with the typical flange yoke balancing techniques. The depth of balance holes is limited by the flange thickness, and the balance hole diameter must be small enough to avoid the companion flange pilot ring on the back face of the flange. Often, one or two small diameter, shallow balance holes do not remove sufficient mass from the heavy side of the flange, and many more holes must be drilled around the periphery of the flange in areas where they are not most effective.
With the increased use of lighter weight, power density materials, such as cast iron, it is often necessary to remove a greater volume of material in the balancing process, i.e., to provide larger balance holes. Manufacturers face potential problems in changing to such lower density materials because there is little room to remove additional weight. These problems can be alleviated by using more care in the earlier manufacturing steps, such as casting and machining, to hold closer tolerances than previously necessary prior to balancing. Smaller tolerances, of course, require additional effort and expense.